Aeroplane engine



" Dec. 2s, 192e.

3 Sheets-Shed 1 Filed Feb. 23, 1918 v@ o E e s |HI|I||||| Il w m UIHIHI I l n u A Y m m m Q m m- In l 11| L0.

Dec. 2s, 1926. l 1,612,313

V. U. D. lPIERCE AEHOPLANE ENGINE Filed Feb. 23, 1918 3 SheetsSheet 2 3mm/tof:

Dec.v 2s, 1926. l A 1,62,313

V. U. D. PIERCE AEROPLANE ENGINE Filed Febz. 23, 1918 :s sheets-sheet 5 Wizz/azz ZZZHnfe @Mommy Patented Dec. 2s, 192,6;

`UNITED STATES PATENT OFFICE.

VIN'I'ON ULRIC DAHLGREN PIERCE, AOF WASHINGTON, DISTRICT 0F COLUMBIA; JOSIAH PIERCE, EXECUTOR OF SAID VINTON U. D. PIERCE, DECEASED.

.AEROPLANE ENGINE.

Application filed February 23, 1918. Serial No. 218,803.

This invention relates to internal combustion engines, and particularly to such engines designed for aeroplanes.

The power developed by an ordinary engine of fixed compression ratio becomes less as the height of the machine above sea level increases. This reduction in power is due to two causes, first, that the/pressure of the atmosphere becomes less as high |altitudes 1G are attained and, second, that owing to the lower density of the air at great heights, the mass of the mixture drawn into the cylinders during one induction period is less than when the machine is on the ground.

lVith these facts in view, the general object of this invention is to provide means whereby thecylinders of an internal combus tion engine may be charged by forced induction and to provide means whereby the same compression pressure may be secured at difi'erent heights, that is to say, means whereby a compression pressure of 5 to 1 for instance may be secured at ground level or up to 10,000 feet altitude and whereby a com- 5 pression pressure of 6 or 7 to 1 0r greater amount may be secured at altitudes higher than 10,000 feet. A

A further object of this invention is to provide means whereby the compression pressure may be varied to any desired degree to correspoml with changes in altitude.

Still another lobject is to provide inan' internal combustion engine having a carbureter and a direct connection froml the car-1 burcter to the cylinders, a pump having a cubic capacity greater than the cubic capacity of any one of the cylinders, and provide means whereby at the will of the operal tor` the charge may either be drawn by the 10 ordinary suction of the cylinders direct from the carburetcr into the cylinders or 'whereby the charge may be drawn by means of the pump "from the ca1l)111'ete1"ind then forced into the cylinders at a greater pressure than atmospheric, thus not only securing forced inductionbut drawing into the pump a greater amount of fuel charge than lcould be drawn into any one of the cylinders and then forcing this charge of greater bulk into the working cylinder of the engine, so as to secure a proper compressionof the charge.

lA further object is to provide in a pump 0f this character, means whereby the length of the stroke of the piston may be adjusted while the engine is running so that the capacity of the pumping cylinder, and-therefore the effective cubic capacity ofthe pumping cylinder, may be controlled, thereby to control the ratio of compression at diiferent altitudes.

Other objects will appear in the course of the following description.

My invention is illustrated in the accompanying drawings, wherein Figure 1 is a side elevation of an aeroplane engine provided'with my improved Pump; i

Figure 2 is a rear elevation of the engine, the pump being in section ;7

Figure 3 is -a longitudinal sectional view through a. pump cylinder and crank' case showing means whereby they stroke of the piston may be increased or reduced;

Figure 4 is a fragmentary sectional view through the shaft 41 transverse to the axis of the shaft; i A

Figure 5 is a like view to Fig. 3 but showing another manner of increasing or decreas. ing the throw of the pistons;

Figure 6 is a fragmentary side elevation of an aeroplane,- engine constructed in accordance with my engine and showing means whereby the inlet of air to the carbureter may be adjusted, in correspondence with the adjustment of the throw of the istons;

Figure 7 is a section on the ine 7-7 of Figure 6; and i Figure 8 is a sectional View of the valve casing 32 and the valve therein showing the valve in position when the fuel is sent directly from the carbureter to the engine cylinders.

In the drawings, I have shown an ordinary type of aeroplane engine, such as is 95 used today on the best and most powerful aeroplanes. In this case, the cylinders 10 are disposed in two rows in angular relation to each other. I have illustrated an eight-cylinder engine, but of course my invention is not limited to this, nor is it limited to the precise arrangement of any engine cylinders. Each cylinder is provided with the usual intake and outlet ports controlled by the usual valve. Inasmuch as .this valve 105 mechanismis well known, it therefore recylinders of the internal combustion engine,

. fuel charge at high altitudes, I provide, in

I provide the usual carbureters 13, each connected by a supply pipe 14 to the-manifold 15 which connects to all of the cylinders on one side. So far this engine is precisely the same as any aeroplane engine.

For the purpose of securing a forced induction and a proper compression of the types of engines having double rows of cylinders, the pumping cylinders 16. These,-

as illustrated in Figure 2, ,have conjoined` crank cases 17 as they maybe called. At its outer end, each cylinder is provided with an inletport 18 and an outlet port 19, ythese ports beine' governed by the valves 20 and 21 respectivelj These valves in turn are governed by any suitable mechanism and I have illustrated for this purpose the ordinary valve operating mechanism common in internal combustion engines, comprising a rocker 22 pivoted intermediate its endsand contacting/alternately with the stems of the valves 20 and'21. This-rocker arm is operated by means of a 'rod 23l in turn connected to a suit-able cam mechanism (not shown), this cam being of well known de-` sign, such as is used for controlling the opening and closing of the ordinary valves of the engine. c

Operating in'eaeh of the cylinders 16 is a piston 24 which is connected by the piston rod 25 to the crank shaft 26 mounted in suitable bearings in the walls of the crank case 17. This crank shaft 2G is illustrated as having mounted upon it a sprocket wheel 27, from. which a sprocket chain 28 passes around a sprocket wheel 29 mounted upon a counter shaft 30 driven from and operatively connected to the main driving shaft or crank shaft of the engine. I do not, of course, wish to be limited to this particular means of transmitting power from the engine shaft to the pump pistons.

Each cylinder 16 has a cubic capacity greater than the cubic capacity of any of the cylinders 10 with which it coacts. The

pump cylinder 16 for instance may be 1A,

larger in cubic capacity or 1/2 larger than the coacting cylinders 10, depending upon the lcompression ressure which is desired to be secured. onnected to the pipe 14 just above the carbureter 13 is a branch pipe 31 which extends to the inlet port 20 of the A corresponding cylinder 16 and disposed at the junction of the pipes 14 and 31 is a directing valve of any suitable form, whose casing is as provided with an arm 33 connected to a controlling rod 34 in turn connected to any suitable actuating means. lVhen this valve is turned in one direction, the charge is allowed to pass directly from the carbureter 13 to the eoacting manifold and cylinders and when the valve is turned to another position, this direct connection is cut off and the charge is directed into the pipe 31, and thus into the pumping cylinders. Leading from the outlet port' 21 of each pumping cylinder is an outlet pipe 35 which communicates with the manifold 15 preferably at its middle. This pipe 35 is provided with a valve 36 designed t cut olf the pump from its connection with the manifold 15 and open communication between the pump vas to connect the carbureter directly with the pipe 14, will connect the pipe 31 with the open air. -Of course the valve 36 is turned to correspond'with the valve 32a and connect the pipe 35 with the open air when the connection between the pipe 35 and the manifold is cut olf. -Any suitable valve arrangement may be used for this purpose. It is, of course, to be understood that a throttle valve ofthe usual type is disposed in connection ,with thecarbureter and between the carbureter and the valve casngr so vas Ito control the passage of fuel either to the pipie 14 or to the pipe 41 in the usual Y manner.

It will be obvious now that under ordinary circumstances and when the machine is say below the 10,000V fopt level, the valve 32` will be shifted so that the fuel `charge will pass directly from the carburetor to 't the manifold 15 and thence into the engine cylinders, but that when the machine has risen above the 10,000 foot level or at any other predetermined altitude, this valve 32 is shifted so as to cause the pump to draw i a relatively .large charge from the carbu- Ireter into thel pump and then force this charge into the manifold 15, and thence into the engine /eylinders at a pressure greater than the a'trnos heric pressure at the level at which themaeiiine is flying.- Thus, though the atmospheric pressure may be very greatly reduced, as for instance onethird at a level of 10,000 feet, yet if the cubic capacity of the pump is a third greater than the cubic capacity of the cylinder, the compression pressure within the cylinder will be the same as when the machine was at ground level or below the 10,000 foot altitude. In other words, the mass of the mixture drawn into the cylinder during the induction period is greater' than when the machine is on the ground in proportion to the height of the machine and hence the heat value of the charge is the same at the 10,000 foot levelA as it is at the ground level, and eliminating air resistance and lift and the resistance of the air to the action of the propellers, in other words, the thrust gf the propeller, the engine will exert as much power at the 10,000 foot level as it will below the 10,000 foot level.

Under ordinary circumstances, a fighting aeroplane flies at an average altitude of about 10,000 feet. Hence `provision -need only be made, to secure proper induction and compression below the 10,000 foot level and onv an average of about 10,000 feet. It is obvious, however, that if means are prol` vided. for still further adjust'ng the effec-` tive capacity of the pumping cylinder, that adjustments may be made for or altitudes.

In Figures 3 and 4 I havev illustrated means to this end, wherein this adjustment of the .effectiverapacity of the pumping cylinders is secured by adjusting the length of the stroke of the pumping piston. In this case the pumping piston 24 is connected to an eccentric rod 37, connected to an eccen-V tric ring 38 of any suitable or usual form and reciprocated by means of an eccentric 89 which is of usualI form exceptr foi1 the fact that it is diametrically slotted, the slot being-designated 40. Through this slot, the shaft 41 passes, this shaft corresponding to the crank shaft 26. The shaft 41 is squared at that portion which engages with the walls of the slot 40 or is otherwise formed to cause a rotation of the eccentricjwithout, however,

lpreventingl the shifting of the eccentric in a direction radial to the shaft 41. The shaft 41 is driven by means of a sprocket wheel 42 in turn engaged by the sprocket wheel 274 previously referred to and this shaft 41 is iollow and has bearing in the walls of the crank case 17.

Slidingly operating within the shaft 41 is a slide 43 which is illustrated as provided with a pair of cam slots 44extending in the same direction and being disposed one ahead of the other. The interior of the shaft 41 is formed with guide slots or grooves 45 for the slide 43, the slide 43 having an easy movementy in these` guide grooves. The slide 43 has a centrally disposed extension or rod 46 extendingout through a cap 47,

at one end of the shaft, and means are provided for'longitudinally shifting the slide 43 which includes a grooved disk, or collar many levels 48 on this shaft engaged by the usual shipper ring 49 in turn connected to a lever or other suitable operating device. It will be obvious now that the extension 46 of the slide may rotate within the slrpper ring 49', but ,that the shifting of the shipper ring will shift the slide from one end of itsstroke to the other.

Pivotally connected to the end walls of the slot 40 in any suitable manner are links 50, these links passing inward through slots in the shaft 41 and being provided wth pin 51 carrying rollers 52 engaging with the walls of the corresponding slot- 44. It' will be obvious now that as theslide 48 is shifted i toward the left (assuming the position of shipper ring will be urged to a positionv of relatively great eccentricity with relation "to the shaft 41 and that as the slide 43 is urged a? in the opposite direction, the ring will be shifted into a position of less eccentriclty. lVhen the slide 43 is shifted to the extreme left as it is in Figure 8, it will be obvious that the stroke of the piston ywill be inff creased and therefore the current or volume of the charge will be increased and that in effect this adjustment of the length of stroke is no more or less than adjusting the effective cubical capacity ofv the pumping cylinder. It will, of course, be understood that theA operating means connected to .the shipper ring 49 will operate over a scale so that the operator will know to what extent he has adjusted the cubic capacity of the pumping cylinder. Inasmuch as the throw of an eccentric is relatively small in com- The crank shaft 27 is formed in two sections having outwardly extending'crank arms 53 which are longitudinally slotted as at 54 and operating in these two slots are the sliding blocks 55 carrying the wrist pin 56 to which the connecting rod 25 is engaged. Sliding upon the crank shaft 2T on each side of the crank are the collars 57, these collars being 'connected by links 58`to the blocks 55, the

links being pivoted to the blocks and to the collars. The collars 57 are'splined or otherwisel enga/'ged with the blocks. to rotate therewith and are provided with Ashipper rings 59. For the purpose of operating these shipper rings and thereby shifting the 'collars 57 longitudinally of the shafts in opposite. directions, I may provide any suitvthe parts illustrated in Figure 3), theA In this figure l it) i able mechanism, but I have illustrated a opposite directions so as to shift the shippery rings toward or from each other and thereby change the angles of the rods 58 and shift the wrist pin supporting blocks outward or inward yrelative to the axis lof the crank shaft. Thelshaft 60 can be 4rotatedeither directly by hand or through reducing gears, and I have illustrated the shaft 60 as being provided with a handle operating over an indicating dial 66 graduated to correspond with the graduations of the barograph,

so that when the latter instrument indicates a certain height, the aviator may shift the handle 65 to the corresponding numeral on his dial 66 and know that the stroke of the piston has been adjusted to correspond with the altitude.' This mechanism, of course, accomplishes the same end as is accomplished by the use of the adjustable eccentric, that is, the end of providing means for adjustably controlling the compression pressure at various altitudes.

It will be noted that with my syste-m of forced induction, and by the use of a pump having a larger cubic capac-ity than the cubic capacity ofthe cylinder, I securenot only the necessary compression pressure at a predetermined altitude to compensate for the rarity of the atmosphere at this altitude, but that I also draw into the pump a suliicient volume of gas to com ensate for the reduction in air pressure. n other words, 1f I simply increase the throw of the piston so as to secure additional compression pres.-Y

sure, I would, not increase the suction power of the cylinder, but by providing for a positive induced feed of fuel into the engine cylinder, I compensate for this reduction of air pressureat the high altitude and at the same time secure the necessary compresslon pressure 1n the cylinder corresponding to this altitude. i l

lWhile I' have illustrated particular embodiments ofimy invention, I wish it 'understood that the principle of the invention may be embodied in yother forms and that I do not wish 'to be'- limited to the details illustrated, either as to'thel form of the pump, its connections to the engine and carbureter, or tol the means whereby vari- -able throw ofthe pump piston is secured. y It 1s,`ofi1course, advisable to increase the amount of air passing throughthe carbureter as the machine rises to higher altitudes and in order thatthis amount of air may be increased relative tothe gasoline, to thus reduce the richness of the mixture, as the machine rises and as the throw of the pistons is adjusted, I may provide a carbureter with thel air inlet ports 67 andI may provide a r0- tary annular valve 68 having air ports 67n which are adaptedfto register with or be placed more or less out ofregister with the air ports 67. I have illustrated this valve as an annulus mounted upon the lower end of thecarbureter and havingr an arm 69 connected by means of a rod 70 to ya lever 7l, the upper end of which lever is operatively connected to the screw rod 62 at the rear end of the engine. Thus, it will be obvious that asfthe piston stroke is reduced, the amount of air entering the carbureter will be likewise reduced and that as the piston stroke is increased, the amount of air entering the carbureter will be correspondingly-increased. l'

It is particularly to be noted that I do not change the form of the engine in any way but that I merely add to the engine a pump of a particular character.A Thus, my invention may be applied to all forms of internal combustion engines designed for flying machines and may be applied, without any change in the valve mechanism, the form or character of the cylinders, or the manner, in which the pistons are connected to the crank shaft of the engine. The invention forming the subject matter of this application con- Stitutes an improvement on the' construction illustrated in my Serial No. 178,692, filed on the 5th day of July,'1917. Having claim is 1. An internal combustion engine including a multiplicity of cylinders each having a piston therein, a carburetcr, a direct connection between the carbureter and the cylinders, a reciprocating pump geared to make two reciprocations to one of a piston and arranged to .supply fuel mixture at substantially maximum pressure. in synchronism with the suction stroke of each cylinder, a connection between the pump and the carbureter and between the pump and each of the cylinders, and means for directing the charge from the carbureter'either directly to the cylinders or cutting oli" the direct connection between the cylinders and carbureter and connecting the carbureter with the Pump' f 2. An explos1on engine including a multlplicity ofl cylinders and pistons working described my invention, what I therein, a carbureter therefor, means for conducting a charge'. from the carbureter directly to the IcyIinderS, a4 reciprocating pump geared. to make two reci rocations to one of each piston and arrang to supply a co-pending application,

fuel mixture at substantially maximum compression in synchronism with the suction stroke of each piston, said pump having a greater capacity than that of any of the cylinders and connected thereto, and means for directing the charge from the carbureter either directly into the cylinders or into the pump and thence to the cylinders.

3. An internal combustion engine having a plurality of cylinders a manifold therefor, a carbureter, a reciprocating pump geared to make two reciprocations to one of cach piston and arranged to supplya fuel mixture at substantially maximum compression in synchronism with the suction stroke of each piston, said pump having a capacity greater than the capacityof any one of the cylinders, and means fordirecting fuel from the carbureter directly into said manifold or into said pump.

4. An internal combustion engine, cornprising a plurality of cylinders and pistons working therein, crank shafts connected to said pistons, a charge forming device, a reciprocating pump geared to make two reciprocations to oneI of each piston, said pump having capacity greater than any one of the cylinders and operated by said crank shaft in synchronism with `said engine, and means for directing a charge ei-ther directly from `the charge forming device to said cylinders or from the charge forming device to the pump and so to the cylinders.

5. An .internal combustion engine for aeroplanes including a pluralit. of cylinders, pistons therein, a crank sha t operatively driven from the pistons, a charge forming device, a pump including a pump cylinder, the pump being driven by the crankshaft, and the cylinder having a cubic capacity greater than the cubic capacity of any one of the cylinders of the engine, a direct tubular connection from the charge forming device to the cylinders, a tubular connection from the charge forming device to the pump and from the pump to said cylinders, and valves shiftable to direct the charge from the charge forming device directlyy to the cylinders, or into said pump and thence to the cylinders, said valves when in a position to cut off the pump from the charge forming device and cylinders providing air inlets and outlets to and from the pump.

6. An `internal --combustion engine comprising a plurality of cylinders and pistons working therein, a charge forming device, and an independent reciprocating pumping means geared to make two reciprocations to one of a piston and to operate in synchronism with each piston to supply a fuel mixture at substantially maximum pressure with the suction stroke of each piston; a direct connection being provided from said charge forming device to said cylinders and a bypass connection by way of said pumping means, and means for variably controlling the stroke of the piston while the pumping means is in operation.

7. The combination with an internal combustion engine having avcylinder, of a charge pump including a cylinder operatively connected to the cylinder of the engine and to amount of air inlet may becut down when the stroke of the piston is decreased, and

increased when the stroke of the piston is increased.

8. The combination with an internal combustion engine having an explosion chamber and a carburetcr, of pumping means adapted to supply a fuel mixture at substantially maximum compression synchronously with the suction stroke, means for variably adjusting the compression of gases within the explosion chamber, and means automatically regulating the amount of air entering the carbureter proportionately to the adjustment of the compression wit-hin the explosion chamber.

9. In an internal combustion engine, the combination with an explosion cylinder, of a charge pump including a cylinder operatively connected to the explosion cylinder, a piston moving in the pump cylinder, means for variably adjusting the throw of the piston, and a carbureter coacting with the pump cylinder and having an air inlet, and" means for automatically regulating the amount f air entering the carbureter in proportion to the adjustment of the piston throw.

10. Ain internal combustion engine including an explosion cylinder, a pump c`ylinder operatively connected to the explosion llO cylinder, a piston operating in the pump cylinder, acarbureter having an air inlet opening, a valve controlling the air inlet opening, means for causing a reciprocation of the piston including an element movable to increase or decrease the throw of the piston, and operative connections between said air valve and said element whereby to shift the air valve in correspondence with the adjustment of the piston throw.

11. A multiple cylinder multi-cycle in.

ternal combustion engine having cylinders with reciprocating pistons therein, a source of fuel supply, a direct connection from the :fuell supply to the cylinder, a pumping device of the reciprocating type geared to make two reciprocations to one of each piston and arranged for supplying a'fuel charge in synchronism with the suction stroke of each piston, a by-pass connection from the fuel supply to the cylinder by way 'of the pumping device, and means for cntting in and cutting out the direct or by-pass connection.

. 12. In a multiple cylinder internal combustion engine, the combination with the intake manifold'and the carbureter, of a reciprocating pump between the carburet-er and the manifold for increasing the quantity of mixture injected into each cylinder, means to lengthen at will the stroke of the pump thereby to increase lthe charge injected by the pump and the compression of the charge to compensate for reduced air pressure and lessened density of the charge at high altitudes, and means for automatically regulating the amount of air entering the carburetor in proportion to the increase in the stroke of the pump.

13. An internal combustion engine comprising a lurality of cylinders and pistons Working t erein, a charge-forming device, and pumfping means for supplying a fuel mixture or each cylinder of a density in excess of that Which would normally be drawn into the cylinder on the suction stroke thereof, a direct connection being provided from said charge-forming device to said cylinders and a by-pass connection by way of said pumping means, and means for variably controlling the delivery capacity of the pumping means in operation.

14. The combination with an -internal combustion engine having a cylinder, and a fuelsource, a force-feed-charge-delivering device connected to the cylinder of the engine and to the source of fuel, means for adjusting the effective delivering capacity of the forcefeed-device ,independent of engine speed, a valve controlling the air inlet to the fuelsource, and an operative connection between said valve and said means whereby the amount of air admitted to the fuel source may be varied as the capacity of the forcefeed device is varied..

15. An internal combustion engine including a plurality of cylinders, pistons therein, a crank shaft operatively driven from the pistons, a charge-forming device, a chargedelivering pump operated inany suitable manner and having a positive fuel delivering capacity in excess of the fuel-suction capacity of `the cylinders on each suction stroke of the engine, a direct 'connection from the charge-forming device to the cylindcrs, a connection from the Charce-forming` device to the pump and from tltie pump to said cylinders, means to direct the charge from the charge-forming device directly to the cylinders,or into said pump and thence' to the cylinders, and atmospheric cut-in and cut-out valves, one on the intake and the other on the delivery side of said charge delivering pump.

16. The combination of an internal com.- bustion engine, a carburetor, a manifold, a force-feed for the carburetor, means for' cutting the force-feed in or out of connection with the carburetor and into and out of connection with atmosphere, and means for varying the positive delivering capacit T of the force-feed during its operation an independently of engine speed.

17. The combination of an internal cornbustion engine, a source of Afuel supply,

' means for delivering the fuel supply to the engine under normal suction action of the engine, force-feed means for delivering the fuel to the engine on each of its suction strokes in an amount in excess of the suction capacity of the piston, and means on the intake and delivery sides of said force-feed device for connecting it partially or wholly with the atmosphere.

In testimony whereof I hereunto affix my signature. VINTON ULRlC DAHLGREN PIERCE. 

